diff options
Diffstat (limited to 'tex/context/base/mkiv/grph-img.lua')
| -rw-r--r-- | tex/context/base/mkiv/grph-img.lua | 50 |
1 files changed, 27 insertions, 23 deletions
diff --git a/tex/context/base/mkiv/grph-img.lua b/tex/context/base/mkiv/grph-img.lua index cde9c8442..795ea4827 100644 --- a/tex/context/base/mkiv/grph-img.lua +++ b/tex/context/base/mkiv/grph-img.lua @@ -29,6 +29,8 @@ local skipbytes = files.skip local setposition = files.setposition local getposition = files.getposition +local newreader = io.newreader + local setmetatableindex = table.setmetatableindex local setmetatablecall = table.setmetatablecall @@ -543,8 +545,8 @@ do if once then for i=1,#t do local l = t[i] - setposition(f,l.offset) - t[i] = readstring(f,l.length) + f:setposition(l.offset) + t[i] = f:readstring(l.length) end local data = concat(t) -- t wiped in caller @@ -553,14 +555,14 @@ do local data = { } for i=1,#t do local l = t[i] - setposition(f,l.offset) - data[i] = readstring(f,l.length) + f:setposition(l.offset) + data[i] = f:readstring(l.length) end return concat(data) end end - function identifiers.png(filename) + function identifiers.png(filename,method) local specification = { filename = filename, filetype = "png", @@ -569,7 +571,7 @@ do specification.error = "invalid filename" return specification -- error end - local f = io.open(filename,"rb") + local f = newreader(filename,method) if not f then specification.error = "unable to open file" return specification -- error @@ -581,44 +583,44 @@ do specification.pagenum = 1 specification.offset = 0 specification.length = 0 - local filesize = getsize(f) -- seek end + local filesize = f:getsize() -- seek end local tables = { } - local banner = readstring(f,8) + local banner = f:readstring(8) if banner ~= "\137PNG\013\010\026\010" then specification.error = "no png file" return specification -- error end while true do - local position = getposition(f) + local position = f:getposition() if position >= filesize then break end - local length = readcardinal4(f) + local length = f:readcardinal4() if not length then break end - local kind = readstring(f,4) + local kind = f:readstring(4) if kind then kind = lower(kind) else break end if kind == "ihdr" then -- metadata - specification.xsize = readcardinal4(f) - specification.ysize = readcardinal4(f) - specification.colordepth = readcardinal(f) - specification.colorspace = readcardinal(f) - specification.compression = readcardinal(f) - specification.filter = readcardinal(f) - specification.interlace = readcardinal(f) + specification.xsize = f:readcardinal4() + specification.ysize = f:readcardinal4() + specification.colordepth = f:readcardinal() + specification.colorspace = f:readcardinal() + specification.compression = f:readcardinal() + specification.filter = f:readcardinal() + specification.interlace = f:readcardinal() tables[kind] = true elseif kind == "iend" then tables[kind] = true break elseif kind == "phys" then - local x = readcardinal4(f) - local y = readcardinal4(f) - local u = readcardinal(f) + local x = f:readcardinal4() + local y = f:readcardinal4() + local u = f:readcardinal() if u == 1 then -- meters -- x = round(0.0254 * x) -- y = round(0.0254 * y) @@ -633,14 +635,16 @@ do tables[kind] = t end t[#t+1] = { - offset = getposition(f), +-- offset = getposition(f), + offset = f:getposition(), length = length, } else tables[kind] = true end - setposition(f,position+length+12) -- #size #kind #crc + f:setposition(position+length+12) -- #size #kind #crc end + f:close() specification.tables = tables return specification end |